1. Field of the Invention
The present invention relates to chair seat and back insert devices, and more particularly to a chair insert back support that positions the user's head and spine aligned with the spine.
2. Description of the Prior Art
Back pain is prevalent in society and often results from relatively minor accidents, constant pushing, pulling, lifting, slipping or falling, or vibrations. Much of such pain occurs in the lower back area. In addition to the suffering of individuals, the cost to society through insurance claims, loss of productivity, and medical care of back pain is extremely high. Back pain often is due to segmental dysfunctions when vertebral joints do not move properly due to misalignment or other causes. Treatment of this type of pain requires returning the spinal column to its normal alignment.
In a normal person, the spine, viewed from the front, forms a straight vertical line, and supports the body from the waist up. The cervical spine, or neck portion, curves forward into a smooth, flexible "C", and supports the head which is about 7% of the body weight. The thoraic spine, or middle back, curves in the opposite direction from the cervical spine, supporting the rib cage and upper body. The ribs prevent the thoraic spine from being very flexible. The lumbar spine, or lower back, curves forward in a flexible "C" in the opposite direction. The fourth and bottom curve is the stable curve formed by the sacral and coccygeal part of the spine. Since the low back supports the upper body, it is under the most stress.
The three spinal curves between the head and the pelvis are termed the cervical lordosis, the thoraic kyphosis, and lumbar lordosis. The curves are normal when the body is standing upright with good posture. Unfortunately, these curves are changed when the body is seated. Most chairs do not give good spinal support, and back aches can develop after extended sitting periods. The distortion of these curves is due primarily to the usual chair design in which the seat slopes to the rear, and the upper back portion of the chair slants rearwardly from the portion attached to the seat.
The usual chair construction tips the superior portion of the pelvis rearwardly which reduces the lumbar lordosis, increases thoraic kyphosis, and decreases the cervical lordosis. These actions places additional stresses on the spine, causing back pain. For persons having lower back pain from an accident, the action of the chair impedes recovery and contributes to pain.
One attempt to provide a chair that will maintain the normal spine curves and alignment is the "backless" chair in which a small, independent seat portion is tipped forward, and the user's body is supported by resting the knees on a pad mounted below and forward of the seat. However, no positive support is provided for the lumbar lordosis. Thus, this chair may not be suitable for treatment of low back pain due to injuries. A device known as the Nada-Chair.RTM. assists in supporting the lumbar lordosis with a sling-type device. A wide back pad is disposed over the lumbar region, and an adjustable looped strap is attached to each edge of the back pad, and the loops are hooked over the wearer's knees while the wearer is seated. The device increases the lumbar lordosis.
The following United States patents disclose devices believed relevant to the present invention: Bridger, U.S. Pat. No. 3.740,096 teaches a hard plastic shell type seat having a seat with a compound curved surface. Berg et al., U.S. Pat. No. 3,749,442 discloses a seat having relatively adjustable sections. Kjersem, U.S. Pat. No. 4,595,234 shows a rocking chair with a short back rest. Yeum, U.S. Pat. No. 4,696,516 describes a two piece airplane and automobile seat contured with compound seat and backrest curves. None of these references is considered to be useful for treating or relieving back pains by aligning the center of gravity of the head over the spine and pelvis.
Thus, there is a need for an insert for existing chairs and seats that will provide a positive support for the lumbar lordosis, and align the user's spine to that of the standing condition for treating and relieving low back pain.